Modulator circuits are used in a variety of data conversion and other applications, in which an analog input signal is to be converted into digital form. One popular form of modulator-based analog to digital converter is known as a Sigma-Delta modulator (SDM, also alternatively referred to as a Delta-Sigma modulator or DSM). In a typical analog-to-digital conversion application, the modulator provides a single-bit data output signal, which is then filtered using a low pass filter to provide a high-resolution digital output, where the filter is known as a decimation filter. In practice, some analog-to-digital conversion applications involve sensing an analog signal that may be at a very high voltage potential relative to the digital system consuming the converted data values. For instance, measurement of the voltage across a current shunt may be used for providing current feedback signals in a control system, where the shunt circuit forms part of a controlled system operating at high voltages. The digital feedback value, on the other hand, may be consumed or used by a microprocessor or other low-voltage circuit, and it is desirable to maintain galvanic isolation between the high and low voltage systems. Accordingly, many current shunt analog-to-digital converters provide the modulator output signal through a capacitively-coupled isolation barrier for subsequent filtering. In operation, the analog input to the modulator circuit is typically an analog voltage signal, and the modulator operates according to a reference voltage. When the input signal is at a top or bottom end of the designed input range, the modulator will output either a series of all one binary value (e.g., logic 1) or the other possible value (0), and the resulting filtered output provides a digital value corresponding to the high or low end of the converter range. However, the receiver circuit on the low-voltage side of the isolation barrier may be subjected to common mode transients, causing the data state of the signal provided to the output filter to toggle even though the actual modulator output is not changing and the analog input voltage has not changed. Accordingly, the subsequent decimation filtering will yield a digital value that appears to change from one end of the conversion range to the other. Accordingly, there is a need for improved data converters and other modulator circuitry to facilitate correct operation in the presence of common mode transients and other noise sources.